1. Field of the Invention
The present invention relates to a battery pack. More particularly, the present invention relates to a secondary battery pack for improved accommodation of a secondary battery.
2. Description of the Prior Art
Recently, electronic appliances having compact sizes with light weight, such as cellular phones, notebook computers and camcorders, have been actively developed and produced. Such electronic appliances are equipped with battery packs so that users can use the electronic appliances in various places even if electric power sources are not separately provided for the electronic appliances. The battery pack includes at least one battery capable of outputting an operational voltage to operate the electronic appliances for a predetermined period of time.
Secondary batteries, which are rechargeable batteries, are currently employed in a secondary pack due to the economical advantages of a battery pack. The secondary batteries include Ni—Cd batteries, Ni-MH batteries and Li secondary batteries, such as Li batteries or Li-ion batteries.
Most secondary batteries include an electrode assembly consisting of a positive electrode, a negative electrode and a separator interposed between the positive electrode and the negative electrode. The electrode assembly is accommodated in a can made from aluminum or an aluminum alloy and the can is sealed by means of a cap assembly. After the can has been sealed by the cap assembly, an electrolyte is injected into the can through an electrolyte injection hole, and then the electrolyte injection hole is sealed, thereby completing the fabrication of the secondary battery. Although iron can be used as a material for the can, if the can is fabricated by using aluminum or an aluminum alloy, the secondary battery has a light weight and is resistant to erosion even if the secondary battery is used for a long period of time under high voltage.
A battery pack is constructed by using a plurality of secondary batteries. In general, a battery pack includes a pack case having an insulation property. In addition, a plurality of batteries, wiring circuits for electrically connecting the batteries to each other, safety devices and contact terminals are accommodated in the pack case for the secondary battery.
For instance, a sealed secondary battery connected with the battery accessories and the safety device, such as a positive temperature coefficient (PTC) device, a thermal fuse and a protective circuit module (PCM), are accommodated in the battery pack. Alternatively, when the secondary battery is connected to the PCM and battery accessories, molding resin is used to fill in gaps formed between the above elements in such a manner that the secondary battery, the PCM and battery accessories may be dad with the molding resin or fixed together, thereby forming the battery pack.
Safety devices are connected to positive and negative electrode terminals of the secondary battery through a predetermined conductor structure called a “lead” in order to prevent the secondary battery from malfunctioning by the interruption of current applied to the secondary battery when the voltage of the secondary battery suddenly rises due to, for example, high temperature in the secondary battery or over-charge/over-discharge of the secondary battery.
However, a conventional pack case for a secondary battery pack is often sized slightly larger than that of products installed in the pack case in order to allow the products, such as the secondary battery, the protective circuit module and the safety device, to be easily installed in the pack case.
For this reason, when the secondary battery, the protective circuit module and other battery accessories are installed in the pack case, they may be jarred when external force is applied to the pack case. If the secondary battery is suddenly moved within the pack case due to external impact applied thereto, the secondary battery may become disconnected from the protective circuit module.